There exists a need for a single device that can culture, ship, and infuse islet. Flasks and petri dishes are the devices currently used to store islets. They are a weak link in the process because these devices have inherent design limitations that do not allow them to maintain islets at high viability during culture or shipping. The problem is the need to oxygenate islets by a gas/medium interface. The net result is that many devices are required for a single transplant, the process is not compatible with regulatory control, and precious islets are lost due to necrosis. There are no commercially available substitutes that offer a superior alternative. This grant is focuses upon creating a gas permeable device that cultures, ships, and infuses islets at high viability in a manner compatible with regulatory control. This device will be superior to any commercially available alternatives. By eliminating the link between oxygen delivery and a gas/medium interface, a device that allows high density culture at high viability becomes available. The islets are at improved oxygen tension, with extra medium capacity, from culture through shipping. Primary and backup device configurations are proposed. One configuration is based on culturing islets at high density in an extremely easy to use device. A backup device integrates a high amount of surface area to house islets at a wide range of possible densities. Aim 1 determines which configuration will be pursued, and creates its design specifications. Of primary interest is the optimal gas permeable surface area to medium volume ratios that indicate device size and shape. Aim 2 produces small scale prototypes of the device and quantifies the performance relative to the flask using porcine and human islets, and provides design specifications for Aim 3. Aim 3 produces full scale device prototypes and quantifies the performance relative to the flask using porcine and human islets. If the novel device proves superior to the flask, specifications of the device will be delivered to Phase II which will investigate making the device suitable for shipping and infusing islets.